I will read and try to make the game better with the advice.I have run many campaigns all the way to level 10. I had the same kind of issues you are having at first because I was treating Dungeon World like it was D&D. You're players have not managed to break the game. The danger is only as real as the fiction, its not really about numbers. You say that you have been playing in line with the advice you have been given but also say that you rely primarily on dealing damage for partial successes.. both of these statements cannot be true. Are you truly here to seek advice for your game or are you just venting? If you are here for advice then re-read this thread, its a goldmine and your next DW game will run a lot better. Also fix the cleric issue by making "draw unwanted attention" something bad. It sounds like your cleric is casting and any time they don't roll a 10+ choosing that outcome so that they can continue using their healing spell. If they always choose the same negative consequence then you didn't make it negative enough.
Regarding my cleric, he hasn't chosen Unwanted Attention as a consequence for 5 months of play. On the rare occasion he rolls a complication (because you don't roll for rotes?) he simply chooses to lose the spell temporarily until the next scene, by which time it's been recovered.